tensor: Add APIs to create and access GstTensor contents

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6000>

subprojects/gst-plugins-bad/gst-libs/gst/analytics/gsttensor.c

@@ -49,6 +49,108 @@ gst_tensor_alloc (gsize num_dims)
 
   return tensor;
 }
+
+static gsize
+size_for_elements (GstTensorDataType data_type, gsize elements)
+{
+  switch (data_type) {
+    case GST_TENSOR_DATA_TYPE_INT4:
+    case GST_TENSOR_DATA_TYPE_UINT4:
+      return (elements / 2) + (elements % 2);
+
+    case GST_TENSOR_DATA_TYPE_INT8:
+    case GST_TENSOR_DATA_TYPE_UINT8:
+      return elements;
+
+    case GST_TENSOR_DATA_TYPE_INT16:
+    case GST_TENSOR_DATA_TYPE_UINT16:
+    case GST_TENSOR_DATA_TYPE_FLOAT16:
+    case GST_TENSOR_DATA_TYPE_BFLOAT16:
+      return elements * 2;
+
+    case GST_TENSOR_DATA_TYPE_INT32:
+    case GST_TENSOR_DATA_TYPE_UINT32:
+    case GST_TENSOR_DATA_TYPE_FLOAT32:
+      return elements * 4;
+
+    case GST_TENSOR_DATA_TYPE_INT64:
+    case GST_TENSOR_DATA_TYPE_UINT64:
+    case GST_TENSOR_DATA_TYPE_FLOAT64:
+      return elements * 8;
+
+    default:
+      g_assert_not_reached ();
+      return 0;
+  }
+}
+
+/**
+ * gst_tensor_new_simple:
+ * @id: semantically identify the contents of the tensor
+ * @data_type: #GstTensorDataType of tensor data
+ * @batch_size: Model batch size
+ * @data: (transfer full): #GstBuffer holding tensor data
+ * @dims_order: Indicate tensor dimension indexing order
+ * @num_dims: number of tensor dimensions
+ * @dims: (array length=num_dims): tensor dimensions
+ *
+ * Allocates a new #GstTensor of @dims_order ROW_MAJOR or COLUMN_MAJOR and
+ * with an interleaved layout
+ *
+ * Returns: A newly allocated #GstTensor
+ *
+ * Since: 1.26
+ */
+GstTensor *
+gst_tensor_new_simple (GQuark id, GstTensorDataType data_type,
+    gsize batch_size, GstBuffer * data,
+    GstTensorDimOrder dims_order, gsize num_dims, gsize * dims)
+{
+  GstTensor *tensor;
+  gsize num_elements = 1;
+  gsize i;
+
+  /* Update this if adding more to GstTensorDataType */
+  g_return_val_if_fail (data_type <= GST_TENSOR_DATA_TYPE_BFLOAT16, NULL);
+
+  g_return_val_if_fail (batch_size > 0, NULL);
+  g_return_val_if_fail (GST_IS_BUFFER (data), NULL);
+  g_return_val_if_fail (dims_order == GST_TENSOR_DIM_ORDER_ROW_MAJOR ||
+      dims_order == GST_TENSOR_DIM_ORDER_COL_MAJOR, NULL);
+  g_return_val_if_fail (num_dims > 0, NULL);
+
+
+  for (i = 0; i < num_dims; i++) {
+    g_return_val_if_fail (dims[i] > 0, NULL);
+    num_elements *= dims[i];
+  }
+  num_elements *= batch_size;
+
+  if (gst_buffer_get_size (data) != size_for_elements (data_type, num_elements)) {
+    g_critical ("Expected buffer of size %zu (%zu elements),"
+        " but buffer has size %zu",
+        size_for_elements (data_type, num_elements), num_elements,
+        gst_buffer_get_size (data));
+    return NULL;
+  }
+
+  tensor = gst_tensor_alloc (num_dims);
+  tensor->id = id;
+  tensor->layout = GST_TENSOR_LAYOUT_STRIDED;
+  tensor->data_type = data_type;
+  tensor->batch_size = batch_size;
+  tensor->data = data;
+  tensor->dims_order = dims_order;
+  tensor->num_dims = num_dims;
+  for (i = 0; i < num_dims; i++) {
+    tensor->dims[i].size = dims[i];
+    if (dims_order == GST_TENSOR_DIM_ORDER_COL_MAJOR)
+      tensor->dims[i].order_index = i;
+    else if (dims_order == GST_TENSOR_DIM_ORDER_ROW_MAJOR)
+      tensor->dims[i].order_index = num_dims - i - 1;
+  }
+
+  return tensor;
 }
 
 /**
@@ -90,3 +192,23 @@ gst_tensor_copy (const GstTensor * tensor)
 
   return copy;
 }
+
+/**
+ * gst_tensor_get_dims:
+ * @tensor: a #GstTensor
+ * @num_dims: (out): The number of dimensions
+ *
+ * Gets the dimensions of the tensor.
+ *
+ * Returns: (array length=num_dims) (transfer none): The dims array form the tensor
+ *
+ * Since: 1.26
+ */
+
+GstTensorDim *
+gst_tensor_get_dims (GstTensor * tensor, gsize * num_dims)
+{
+  if (num_dims)
+    *num_dims = tensor->num_dims;
+  return tensor->dims;
+}

subprojects/gst-plugins-bad/gst-libs/gst/analytics/gsttensor.h

@@ -153,12 +153,24 @@ G_BEGIN_DECLS
 GST_ANALYTICS_META_API
 GstTensor * gst_tensor_alloc (gsize num_dims);
 
+GST_ANALYTICS_META_API
+GstTensor * gst_tensor_new_simple (GQuark id,
+    GstTensorDataType data_type,
+    gsize batch_size,
+    GstBuffer * data,
+    GstTensorDimOrder dims_order,
+    gsize num_dims,
+    gsize * dims);
+
 GST_ANALYTICS_META_API
 void gst_tensor_free (GstTensor * tensor);
 
 GST_ANALYTICS_META_API
 GstTensor * gst_tensor_copy (const GstTensor * tensor);
 
+GST_ANALYTICS_META_API
+GstTensorDim * gst_tensor_get_dims (GstTensor * tensor, gsize * num_dims);
+
 GST_ANALYTICS_META_API
 GType gst_tensor_get_type (void);
 

subprojects/gst-plugins-bad/gst-libs/gst/analytics/gsttensormeta.c

@@ -58,6 +58,11 @@ gst_tensor_meta_api_get_type (void)
 }
 
 
+/**
+ * gst_tensor_meta_get_info: (skip)
+ *
+ * Since: 1.26
+ */
 const GstMetaInfo *
 gst_tensor_meta_get_info (void)
 {